The 66-year-old retired high school teacher and track coach needs the device to pump blood through his body as he waits for a human heart donation. The device was implanted earlier this year and the procedure was announced Thursday.

James Carelli Jr. was diagnosed in 2011 with a disease that made a protein in his blood thicken his heart and caused other organs to start to fail.

Officials at the Boston hospital say the South Shore resident’s health has improved dramatically since his February surgery.

“If I didn’t have this device, I would not be here,” Carelli said.

“This is the bridge to a transplant and we’re going to make it,” his wife Jane said.

Carelli also is on a waiting list for a kidney transplant.

While he walks on a treadmill now, Carelli says he’d probably be outside running if he wasn’t attached to a machine that pumps the device in his chest.